It seems like you have isolated the problem to the turntable. I don’t know much about usb turntables but I assume the usb is there potentially to record the lp to a hard drive, and that if you are just playing an lp without recording it, it isn’t the source of the problem. I am also assuming that the turntable has a built in phono preamp.
Imo the problem is with either 1) the built in preamp, 2) the cartridge 3) the wiring (cables). You don’t mention what kind of an amplifier the turntable is connected to. I would check the connections from the turntable to the amp because it’s possible that one channel is either loose or or perhaps the is dirt at one contact point. If that doesn’t work try a different pair of cables, because the cables themselves might be damaged.
If the cables aren’t the issue, imo it’s the phono pre amp. Internal pre amps on a budget table are not likely to be high quality. If you are using the internal pre amp, try to borrow an external pre amp and see if that solves it. If it does, then you can proceed accordingly.
If all that fails, then the problem may be with the cartridge and/ or it’s wiring